/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.flink.tsfile;

import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.typeutils.ResultTypeQueryable;
import org.apache.flink.api.java.typeutils.RowTypeInfo;
import org.apache.flink.types.Row;
import org.apache.iotdb.tsfile.common.constant.QueryConstant;
import org.apache.iotdb.tsfile.read.common.Field;
import org.apache.iotdb.tsfile.read.common.Path;
import org.apache.iotdb.tsfile.read.common.RowRecord;

import java.util.List;
import java.util.stream.Collectors;

/**
 * The parser that parses the RowRecord objects read from TsFile into Flink Row object.
 */
public class RowRowRecordParser implements RowRecordParser<Row>, ResultTypeQueryable<Row> {

    private final int[] indexMapping;
    private final RowTypeInfo rowTypeInfo;

    public RowRowRecordParser(int[] indexMapping, RowTypeInfo rowTypeInfo) {
        this.indexMapping = indexMapping;
        this.rowTypeInfo = rowTypeInfo;
    }

    @Override
    public Row parse(RowRecord rowRecord, Row reuse) {
        List<Field> fields = rowRecord.getFields();
        for (int i = 0; i < indexMapping.length; i++) {
            if (indexMapping[i] < 0) {
                // The negative index is treated as the marker of timestamp.
                reuse.setField(i, rowRecord.getTimestamp());
            } else {
                reuse.setField(i, toSqlValue(fields.get(indexMapping[i])));
            }
        }
        return reuse;
    }

    private Object toSqlValue(Field field) {
        if (field == null) {
            return null;
        } else if (field.getDataType() == null) {
            return null;
        } else {
            switch (field.getDataType()) {
                case BOOLEAN:
                    return field.getBoolV();
                case INT32:
                    return field.getIntV();
                case INT64:
                    return field.getLongV();
                case FLOAT:
                    return field.getFloatV();
                case DOUBLE:
                    return field.getDoubleV();
                case TEXT:
                    return field.getStringValue();
                default:
                    throw new UnsupportedOperationException(
                            String.format("Unsupported type %s", field.getDataType()));
            }
        }
    }

    @Override
    public TypeInformation<Row> getProducedType() {
        return rowTypeInfo;
    }

    /**
     * Creates RowRowRecordParser from output RowTypeInfo and selected series in the RowRecord. The
     * row field "time" will be used to store the timestamp value. The other row fields store the
     * values of the same field names of the RowRecord.
     *
     * @param outputRowTypeInfo The RowTypeInfo of the output row.
     * @param selectedSeries    The selected series in the RowRecord.
     * @return The RowRowRecordParser.
     */
    public static RowRowRecordParser create(
            RowTypeInfo outputRowTypeInfo, List<Path> selectedSeries) {
        List<String> selectedSeriesNames =
                selectedSeries.stream().map(Path::toString).collect(Collectors.toList());
        String[] rowFieldNames = outputRowTypeInfo.getFieldNames();
        int[] indexMapping = new int[outputRowTypeInfo.getArity()];
        for (int i = 0; i < outputRowTypeInfo.getArity(); i++) {
            if (!QueryConstant.RESERVED_TIME.equals(rowFieldNames[i])) {
                int index = selectedSeriesNames.indexOf(rowFieldNames[i]);
                if (index >= 0) {
                    indexMapping[i] = index;
                } else {
                    throw new IllegalArgumentException(
                            rowFieldNames[i] + " is not found in selected series.");
                }
            } else {
                // marked as timestamp field.
                indexMapping[i] = -1;
            }
        }
        return new RowRowRecordParser(indexMapping, outputRowTypeInfo);
    }
}
